GRAV01 (Experiment for measurements of speed of propagation of gravity) 2002 September 08 Notes prepared by Leonid Petrov, NVI/GSFC ( pet@leo.gsfc.nasa.gov ) Station CODE Code # tapes # of obs Start Time End Time Algonquin G Ap 2 108 September 08, 08:15 September 08, 21:04 UT Fairbanks A Gc 3 130 September 08, 11:06 September 09, 03:03 UT HartRAO J Hh 2 86 September 08, 06:00 September 09, 06:00 UT Kokee K Kk 2 105 September 08, 13:39 September 09, 02:13 UT Medicina B Mc 3 108 September 08, 06:00 September 09, 06:00 UT Ny Alesund N Ny 4 198 September 08, 06:04 September 09, 05:42 UT Westford E Wf 2 116 September 08, 07:50 September 09, 20:49 UT Wettzell V Wz 3 117 September 08, 06:00 September 09, 06:00 UT Long gaps: HartRAO does not observe between September 08, 12:20 and Sept. 09, 03:14 UT Medicina does not observe between September 08, 15:18 and Sept. 09, 02:05 UT Westford does not observe between September 08, 15:35 and Sept. 09, 02:05 UT Purpose ======= This is the MAIN experiment in the series of two experiments for measurement of gravity speed propagation. The schedule is designed for precise measurement of the change of the angular distance between the target quasar, 0839+187, and two calibrators within a session. The Jupiter will pass 3.7 arcmin from the target quasar, 0839+187, at 15h 55m 36.9s UTC 2002.09.08. The theory based on general relativity predicts ( Kopeikin, S.M. "Testing the relativistic effect of the propagation of gravity by very long baseline interferometry", ApJ Lett., vol. 556, p. L1-L5, 2001 ) a special term for the differences in phases between the target and two calibrators. This phase difference changes in the range of 3-15 degrees during 3-10 hours before and after passing Jupiter due to the fact that according to general relativity gravity propagates with the same speed as light in vacuum. Measurements of this term would allow confirmation of the validity of general relativity for a NON-STATIONARY gravitation field. Up to now, no direct tests of such kind have been done. Passing the Jupiter within several arcmin of a strong quasar is a unique event. There will be no similar events till 2010. It is impossible to repeat this experiment in the case of failure. Refer to http://gemini.gsfc.nasa.gov/pet/discussion/grav/grav.html for more details. =================================================================== SKED Summary from file ./grav01.skd for experiment GRAY01 (all scans with at least one subnet station) Calculating rise/set times for source 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 5 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76... done. Average number of obs. per baseline per source (normalized by up-time) = 1.6 Min = .0 Max = 89.8 (Baseline Hh-Mc on 0839+187) RMS = 8.4 Total time: 1439 minutes ( 24.0 hours). Key: Ap=ALGOPARK Gc=GILCREEK Hh=HARTRAO Kk=KOKEE Mc=MEDICINA Ny=NYALES20 Wf=WESTFORD Wz=WETTZELL Ap Gc Hh Kk Mc Ny Wf Wz Avg % obs. time: 36 52 27 40 38 75 39 39 43 % cal. time: 0 0 0 0 0 0 0 0 0 % slew time: 5 1 5 0 2 1 1 1 2 % idle time: 57 46 66 58 59 22 58 59 53 # of tapes : 1.8 2.6 1.4 2.0 2.3 4.0 2.0 2.4 total # scans: 108 130 86 105 108 198 116 117 121 # scans/hour : 4 5 3 4 4 8 4 4 5.0 Avg scan (sec): 290 347 280 334 304 327 297 290 308 tape change times (hhmm): 1620 1720 0314 2048 1227 1227 1449 1227 0000 2313 0000 0000 0416 1832 0000 0416 0000 0000 0000 0000 0000 0009 0000 0000 # OF OBSERVATIONS BY BASELINE | Ap Gc Hh Kk Mc Ny Wf Wz StnTotal ---------------------------------------------- Ap|108 70 32 49 44 88 98 48 429 Gc| 130 5 96 31 110 69 36 417 Hh| 86 0 80 76 35 79 307 Kk| 105 6 92 57 12 312 Mc| 108 96 44 103 404 Ny| 198 96 106 664 Wf| 116 51 450 Wz| 117 435 Number of 2-station scans: 10 Number of 3-station scans: 71 Number of 4-station scans: 70 Number of 5-station scans: 37 Number of 6-station scans: 38 Number of 7-station scans: 6 Number of 8-station scans: 0 Total # of scans, observations: 232 1709